With recent improvements in processor, storage and networking technologies, today's wireless communications devices take many different forms, and offer a number of innovative features. Examples of this new class of wireless communication devices include personal digital assistant's (or, PDA's) fitted with a wireless communications interface, two-way paging devices, digital communications devices, and third-generation (or, 3G) personal communicators. Gone are the days when such devices are merely used to support verbal communication. Today, consumers are demanding that such devices be multifunctional, enabling a user to receive and/or retrieve email, to send/receive text messages, and to access text-based content from the Internet (e.g., stock quotes, flight arrival/departure information, etc.). Despite the recent innovation in the wireless communication space, consumers are demanding even greater application resources and functionality for their portable communications device. For example, despite recent advances in the functionality and capability of wireless access devices, no good solution exists for streaming media content over heterogeneous networks (e.g., a media streaming path comprising a wired network component and wireless network component).
Those skilled in the art will appreciate that streaming media content over a heterogeneous network comprised of a wired component and a wireless component is a very challenging task. One reason is that the transport layer protocol associated with each of the disparate components was developed independent of one another and, therefore, without regard for many of the design challenges of the other. For example, the control algorithm of a typical wireline transport layer protocol (e.g., TCP, UDP, etc.) assumes that any degradation in transmission quality is due to congestion problems in one or more of the network elements (e.g., router, switch, hub, etc.). Accordingly, conventional transport layer protocols will iteratively reduce the transmission rate until transmission quality is improved. However, in heterogeneous networks that include a wireless network component, the degradation in transmission quality may have nothing to do with congestion on the wireline component of the communication channel. That is, the degradation in transmission quality, measured in terms of a bit-error rate (or, BER), may well be caused by a fading condition, a shadowing effect, multi-path sources, etc. in the wireless communication channel. It will be appreciated that reducing the transmission rate (assuming a congestion condition) will not improve transmission quality when the actual problem is a fading condition in the wireless component of is the communication channel. Despite such limitations, conventional transport layer protocols are often employed to provide the limited (often text-based) Internet content available to wireless devices. As a result, the wireless Internet access user experience is often disappointing.
Another limitation associated with such heterogeneous networks is error control in a scalable wireless communication channel. Conventional wireless error control schemes often employ a simple threshold, wherein if the BER of a packet exceeds the threshold, the packet is dropped. The assumption is that a couple of lost packets during the course of verbal communication will not be too offensive to the users of the system. If the number of dropped packets exceeds a certain threshold, the system may take corrective action, e.g., attempt to transition to a more reliable communication channel. Alternatively, the system will drop the call and the participants can attempt to reestablish the connection. While these often represent minor (although irritating) inconveniences for the user, they are accepted as a fact of life. When these same assumptions are employed in the data-intensive task of streaming multimedia content over a wireless channel, the minor inconvenience degrades into an unacceptable user experience, thereby limiting adoption of wireless multimedia streaming technology.
Thus, what is required is an architecture and related methods for streaming media content over heterogeneous networks, unencumbered by the limitations commonly associated with the transport layer protocol of conventional streaming architectures. Just such a solution is presented in the disclosure to follow.